1 INTRODUCTION The reason to choose the dissertation According to the guideline of National Comprehensive Cancer Network (NCCN) or European Head and Neck Society-European Society for Medical Oncology- European Society for Radiotherapy and Oncology (EHNS-ESMO-ESTRO), concurrent chemoradiotherapy (CCRT) with or without adjuvant chemotherapy is recommended for nasopharyngeal carcinoma (NPC) stage II-IVB The role of this modality on local-regional control and metastasis prevention has been proved by many randomized studies for stage III-IVB For stage II NPC, there were several studies on chemoradiotherapy, however, the evidence of the effectiveness has been not strong enough Apart from the supporting views, there are controversies about the role of this regiment Some researchers suggests it is possible that chemotherapy has been overused in clinical practice without substantial survival gain, especially in the IMRT era Moreover, the use of chemotherapy may increase the rate of acute and chronic toxicities affecting to the patients quality of life, which is very important issue for the early stage patients who have opportunity of long time survival In Vietnam, most of studies on the role of chemoradiotherpy were conducted for stage III-IVB NPC, but not for stage II Purposes Evaluate the clinical and some subclinical characteristics of stage II nasopharyngeal carcinoma Assess the effect of concurrent chemoradiotherapy and several toxicities The contribution of the thesis NPC stage II was more common in male than female (male/female: 1.8/1) The age group of 40-59 was most common (66.2%) Cervical lymph node (LN) was the first clinical symptom and most common at the time of hospitalization (33.9%, 90.3%) The time of hospitalization < months was highest (56.5%) Parapharyngeal space (PPS) invasion: 45.2% Level II LN was prominent (87.5%) The size of LN was mostly < 3cm (T2N0, T1N1, T2N1 were 9.7%; 54.8%; 35.5%, respectively) The undiferrentiated carcinoma of nasopharyngeal type (UCNT) was most frequent (96.7%) Tumour and LN complete response rate (CRR) and partial response rate (PRR): 93.5% and 6.5% 1,2, 3-year overall survival (OS): 100%; 93.4%; 88.7%, respectively Medium survival time: 41.3 months 2 3-year disease free survival (DFS) rate: 86.0% The poor prognosis for the OS: PPS invasion, ≥3-6cm LN, delay time of treatment > weeks (p